| /* ISO10126.java -- An implementation of the ISO 10126-2 padding scheme |
| Copyright (C) 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
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| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.pad; |
| |
| import gnu.java.security.Registry; |
| import gnu.java.security.util.PRNG; |
| |
| /** |
| * The implementation of the ISO 10126-2 padding algorithm. |
| * <p> |
| * The last byte of the padding block is the number of padding bytes, all other |
| * padding bytes are random. |
| * <p> |
| * References: |
| * <ol> |
| * <li><a href="http://www.w3.org/TR/xmlenc-core/">XML Encryption Syntax and |
| * Processing</a> Section "5.2 Block Encryption Algorithms"; "Padding".</li> |
| * </ol> |
| */ |
| public final class ISO10126 |
| extends BasePad |
| { |
| /** Used to generate random numbers for padding bytes. */ |
| private PRNG prng; |
| |
| ISO10126() |
| { |
| super(Registry.ISO10126_PAD); |
| prng = PRNG.getInstance(); |
| } |
| |
| public void setup() |
| { |
| // Nothing to do here |
| } |
| |
| public byte[] pad(byte[] in, int offset, int length) |
| { |
| int padLength = blockSize - (length % blockSize); |
| final byte[] pad = new byte[padLength]; |
| |
| // generate random numbers for the padding bytes except for the last byte |
| prng.nextBytes(pad, 0, padLength - 1); |
| // the last byte contains the number of padding bytes |
| pad[padLength - 1] = (byte) padLength; |
| |
| return pad; |
| } |
| |
| public int unpad(byte[] in, int offset, int length) |
| throws WrongPaddingException |
| { |
| // the last byte contains the number of padding bytes |
| int padLength = in[offset + length - 1] & 0xFF; |
| if (padLength > length) |
| throw new WrongPaddingException(); |
| |
| return padLength; |
| } |
| |
| /** |
| * The default self-test in the super-class would take too long to finish |
| * with this type of padder --due to the large amount of random data needed. |
| * We override the default test and replace it with a simple one for a 16-byte |
| * block-size (default AES block-size). The Mauve test TestOfISO10126 will |
| * exercise all block-sizes that the default self-test uses for the other |
| * padders. |
| */ |
| public boolean selfTest() |
| { |
| return test1BlockSize(16, new byte[1024]); |
| } |
| } |